Our studies on the carbohydrate associated with lens proteins indicated that the protein with the highest level of sugar was found in the gamma crystallin fraction. The amount of sugar was found in the gamma crystallin fraction. The amount of sugar associated with the gamma crystallin fraction appeared to increase with age. Closer scrutiny revealed that the bulk of the carbohydrate was not associated with any of the major crystallins, but with a minor protein component. This carbohydrate rich protein eluted before the gamma peaks on a SE- Sepahdex column and did not appear to belong to gamma crystallins. In our quest to find the source of the glycoprotein we turned our attention to the lens membranes. For this study, cattle lenses, stripped of capsule and epithelium, were used. The plasma membranes were isolated in a particular fraction by sucrose-gradient centrifugation. The plasma membranes were extracted by detergents and the proteins analyzed by polyacrylamide gel electrophoresis in SDS. The gel revealed a complex pattern of protein bands most of them unrelated to the crystallins. There were 4 main protein bands that stained strongly with PAS. The carbohydrate of the membrane glycoproteins was composed of fucose, xylose, mannose, galactose, glucose, hexosamine and sialic acid. Studies to establish the optimal conditions to culture epithelial cells of lenses from normal and cataractous mice are being continued. Tissue culture has led to lentoid bodies which appear very much like lens fiber under electron microscopic examinations. Purification of gamma crystallin from mouse lens has been accomplished and antiserum to it is now being prepared. Gamma-crystallin is a protein synthesized in the lens fiber but not in the epithelium. Use will be made of the fluorescent antibody to gamma crystallin to determine whether or not gamma crystallin is present in these lentoid body. By these means we hope to show that the tissue cultured cells retain the differentiative characteristics of lens cells.